A note on discounting and the social time preference rate

This paper examines the discounting of money values in social evaluations using a social time preference rate (defined as the sum of a pure time preference rate and the product of the elasticity of marginal valuation and a growth rate). It is shown that this procedure can give a different ranking of alternative streams compared with the direct use of the pure time preference rate to discount ‘social welfare’ in each period (where social welfare is a - usually isoelastic - function of money values).